n,v,c = map(int,input().split())
V = []
W = []
for i in range(n):
    a,b = map(int,input().split())
    W.append(a)
    V.append(b)

dp = [[0]*(v+1) for _ in range(n+1)]

for i in range(n):
    for j in range(v+1):
        dp[i+1][j]=dp[i][j]
        if(j-W[i]>=0):
            if(dp[i+1][j]<dp[i][j-W[i]]+V[i]+c):
                dp[i+1][j]=dp[i][j-W[i]]+V[i]+c
            # dp[i+1][j]=max(dp[i+1][j],dp[i][j-W[i]]+V[i])
        if(j-W[i]>=0):
            dp[i+1][j]=max(dp[i+1][j],dp[i+1][j-W[i]]+V[i])

print(dp[-1][-1])